Self-aligning switch



Oct. 17, 1961 c. e. ZEMELS EI'AL 3,005,063

SELF-ALIGNING' SWITCH Filed Feb. 27, 1959 4 Sheets-Sheet 1 Oct. 17, 1961c. G. ZEMELS ETAL 3,005,063

SELF-ALIGNING' SWITCH 4 Sheets-Sheet 2 Filed Feb. 27, 1959 NOEnvnewrwes. 6'41?! 6. ZM6Z5 filo/ 105 3, den

SM LXMJ wywu a u a Oct. 17, 1961 Filed Feb. 27, 1959 C. G. ZEMELS EI'ALSELF-ALIGNINGi SWITCH 4 Sheets-Sheet 3 United States Patent 3,005,063SELF-ALIGNING SWITCH Carl G. Zemels, illayton, and Thomas B. Ortwrg,Florissani, l t '10., assignors to James R. Kearney Corporation, St.Louis, M0., a corporation of Delaware Filed Feb. 27, 1959, Ser. No.796,029 8 Claims. (Cl. 200-48) This invention concerns high-voltage,high-current electrical switches, and particularly those of the type inwhich a rotary switch blade mounted on an insulator can swing into andout of contact with a contact structure mounted on another insulator.

it has been found that in the practical use of rotary blade typeswitches, the base on which the insulators are mounted often becomesbent or twisted, or both, during installation or use. This type ofdamage can occur either through mechanical abuse during handling orthrough warpage of the wood of the crossarms on which the switch isinstalled. The deformation is usually so slight that it is hard todetect in and of itself, but due to the lever arm formed by theinsulators and the blade, it can easily result in a substantialmisalignment of the blade tip with respect to the contact structure. Ifthis misalignment is sufficiently great, the blade may engage only oneof the contact jaws, or it may still engage both contact jaws, out thequality of current transfer will be substantially reduced by a changefrom line-contact to point-contact due to twist in the base, and/or by aconsiderable difference in the contact pressure due to bending of thebase. With such greatly lowered quality of current transfer, the switchwill overheat and eventually be destroyed.

Another difficulty in the use of ordinary rotary-blade switches iscaused by the accumulation of ice between the contact jaws under severeweather conditions. Removal of the ice by a mere shearing motion of theblade between the contacts is feasible but this technique requiresstrength and imposes an undesirable mechanical strain on the operatinglinkages in three-phase banks.

The switch of our invention is designed to overcome these difiicultiesby mounting the switch blade for limited omnidirectional movement, so asto automatically compensate for any misalignment, and by providing anovel contact structure, the effect of which is to break off any iceaccumulated on the contacts by a hinge-like rotary motion which requiresconsiderably less force than was previously necessary. At the same time,the hinge-like motion results in improved wiping of the switch bladeagainst the contact jaws.

It is, therefore, an object of our invention to provide a switch whichis capable of self-alignment within predeterminable limits.

It is a further object of our invention to provide a rotatable contactstructure having improved ice-breaking properties and an improvedcontact wiping action.

It is a still further object of our invention to provide an efiicientand rugged side-break switch having only two supporting insulators.

We will now describe a preferred embodiment of our invention, referencebeing had to the drawings'in which:

FIGURE 1 is a side elevation of the switch, of our. invention;

FIGURE 2 is a plan view of the switch in its closed position;

FIGURE 3 is a plan view of the switch in partly open position;

FIGURE 4 is a section along line 4-4 of FIGURE 1 showing the contactstructure and arcing horns;

FIGURE 5 is a vertical section through the rear insulator along line 5-5of FIGURE 1;

FIGURE 6 is a vertical section through the contact structure along line6-6 of FIGURE 2;

FIGURE 7 is a detail plan view of the operating mechanism;

FIGURE 8 is a horizontal section along line 8-8 of FIG. 6; and

FIGURE 9 is a perspective cut-away view of the universal bearing.

Generally our switch consists of a pair of insulators mounted on a base.One of the insulators is rotatable and carries at its top a switch bladewhich rotates with the insulator into and out of contact with a contactstructure mounted on the second fixed insulator. The switch blade isjournalled for limited motion in a universal. bearing, and the bladeterminal is so mounted on the top of the rotary insulator that it doesnot rotate with the insulator and blade.

The contact structure consists of a pair of flared jaws which arerotatably mounted on the top of the fixed insulator, and which arespring-biased together at a point between their axis of rotation and theswitch blade for a reason hereafter explained. Conventional arcing hornsare provided to prevent formation of an are between the switch blade andthe contact structure during the opening movement of the switch blade.

Electrical contact between the blade terminal and the blade isestablished through the universal hearing by highly machined circularcontact surfaces which are subjected to a moderate compressive force. Inthe case of the bearing allowing vertical motion of the blade; thisforce is the result of tightening the bolts on the bearing shaft to thedesired tightness; in the bearing allowing axial rotation of the switchblade, and in the hearing which connects the blade terminal assembly tothe rear insulator assembly, a spring washer and a coil springrespectively, are used to urge the circular contact surfaces together.Provisions are made in the design of the parts of the universal bearingfor limiting the movement of the switch blade with respect to itsmounting structure, so as to prevent any over-compensation which mightresult in failure of the blade to engage the contacts during the closingmotion.

The contact supporting plate is likewise equipped with a pair of currenttransfer rings against which matching surfaces of contact pieces areurged by a spring. Because of the fact that when the switch bladeengages the contacts, it tends to force the contact pieces apart andthus to make them non-parallel, the spring which urges the contactpieces together is located eccentrically of the current transfer rings.Thus the pressure of the spring compensates for the spreading of thejaws by the blade and results in holding the contact pieces parallel.This arrangement assures intimate contact between the current transferrings on the contact pieces and those on the contact supporting bladeover the entire area of the current transfer rings. A tie bolt tying thecontact jaw pieces together is also provided to prevent one of thecontact jaws from becoming spaced from the switch blade when a suddenmagnetic force, such as may be engendered by a fault current, suddenlyforces the switch blade sharply against the other contact jaw.

Referring now to the drawings, switch 10 is mounted on abuse 12, whichin turn may be attached to a crossarm' or other suitable mountingsurface (not shown). Mounted near the rear end of base 12 (the left endin FIGURE 1') is a rotatable insulator 14 which can be turned by pullingoperating handle 16. The operating handle 16 is limited in its movementby adjustable stop screws 20 threaded into brackets 18. A terminalmember 22 is mounted on the top of insulator 14 in such a manner that itcan rotate about shaft 24. Electrical contact is established betweenmember 22 and the blade support 26, which is'fixedly 3 attached toinsulator '14, by highly machined circular contact surfaces 25, 27 (FIG.5) which are pressed together by a coil spring 28. The contact surfaces25, 27 are protected from the weather'by a fiexible'sleeve 232:. In use,the terminal member 22 is held in a' fixedposition with respect to base12 by the line wire (not shown) attached to it.

Since the line wiremay be quite heavy in some installations, the uppercontact surface is not quite flat, but very slightly convex (shown ingrossly exaggerated form in FIGURE 5), so that an excessiveweighthanging from terminal member 22 will cause a rocking motion of itsextremity 23 resulting in a shifting of the contact line betweensurfaces 25 and 27 toward the outside of the circle. At the sometime,the rocking of member 22 may cause the surfaces 25 and 27 toseparate minutely at a location diametrically opposite the terminal 21.H ws,oob,oes

ever, the excess pressure resulting from the'excessive weight willcompensate for the loss of contact area between surfaces 25 and 27, sothat the total current-carrying capacity of the bearing 25, 27 will notbe impaired. If it were not for the convexity of surface 25, rocking ofmember 22 would result in a contact only at theoutward edge of thecontact circle, where not as as much clean contact area would beavailable.

Blade support 26 terminates in a pair of ears 36 which are traversed bya horizontal shaft 32 on which an intermediate member 38 is journalledfor rotation about shaft 32 in a clockwise or counter-clockwisedirection as seen in FIGURES 1 and 9. Movement of the switch blade aboutits own axis is permitted by a second shaft 34'forming part of bladeholder 36, which is journalled in a longitudinal bore 33 of intermediatemember 38. The shaft 34 has a hole 35 formed therein. The hole 35 isslightly larger than the shaft 32 which extends therethrough, so thatshaft 34 can be rotated through an arc of about six degrees at eitherend of which an edge of he hole 35 will strike the shaft 32 to preventfurther rotation of shaft 34.

Rotation of the intermediate. member 38 about shaft 32 is limited byapin 37 mounted on an extension 39 of intermediate member 38. The pin 37can move back and forth between cars 41 of bladesupport 26. Compressivepressure is exerted on high conductivity contact rings 31a by tighteningbolt 27, and on contact rings 31b by the spring washer 29 (FIG. 9). Foroptimum operation of the switch, the pressure on each bearing should bythe smallestpressure which will allow sufiicient current transferthrough the. highly machined contact rings 31a and 31b. Blade holder 36is equipped with a cradle 49 in which the switch blade 5-2 is firmlyheld by a pair of U-bolts 44 (HG. l). Rotation of blade 42 with respectto cradle is prevented by a pin 43 which extends through blade 42 andengages a slot 45 (FIG. 9) in the bottom of cradle 40. This slot issufficiently long to permit enough longitudinal movement of blade 42 toallow proper positioning of blade 42 after installation by merelyloosening U-bolts 44 and moving blade 42 forward or backward asnecessary.

It will be seen from the foregoing that blade 42 is in effectuniversally journalled with respect to blade support 26. The blade 42terminates at its forward end in a flat paddle-like silver-plated tip46.-An arcing rod is attached to the blade 42 by a bracket 59, andduring opening movement of the switch, the forward top portion of thearcing rod 48 engages arcing horns 52 and 54 which are mounted onsupporting plate 69, and hence electrically connected to forwardterminal 56, until after the main contacts have opened.

Contact terminal 56 is attached to the fixed insulator 58 mounted on theforward end of base 12, by a supporting plate 69. A contact bearingplate 62 is firmly attached to the supporting plate 6! The contactbearing plate 62 carries near its rear (i.e., right in FIG. 6) extremitya pair of highly machined high conductivity current trans- .fer. rings61'which match corresponding rings 63 on the forward extremities ofcont-act pieces 67 and 69. A

' of slot 65 limits the rotation of the contacts to about thirty degreesin our preferredembodiment. The purpose of protuberances 75 is toincrease the length of the bores 73, into which bolt 71 is snuglyfitted, so as to give bolt 71 greater leverage in maintaining contactpieces 67 and 69 parallel. A pair of springs 72 surround the ends ofbolt 71 and the protuberances 75 for the purpose of urging the jaws 66,68 together with the required contact pressure which, in our preferredembodiment, is about ninety pounds. Collars 74a coacting with washers74b are provided to prevent excessive compression of the springs 72 whennuts 74c of bolt 71 are tightened. Inasmuch as the springs 72 areeccentrically located with respect to shaft 70, their pressurecompensates for the stress caused by theblade tip 46 being insertedbetween the jaws 66, 68. This stress would normally tend to rendercontact pieces 67, 69 nonparallel, but because of the springs 72 optimumparallelism is achieved when the blade tip 46 is in position betweenjaws 66, 68 so that the maximum current transfer capacity of rings 61,63 will be utilized.

A bolt 77 is further provided rearwardly of the bolt 71 for the purposeof preventing the jaws 66, 68 from becoming separated any farther thannecessary to admit blade tip 46. Consequently, the magnetic field set upby a sudden current surge will be unable to push tip 46 so hard againstone of the. jaws that the contact with the other jaw becomesmomentarilybroken, a condition which would result in a destructive are between thetip 46 and the other jaw. The contact structure is protected from theweather by a hood 64 attached to the forward end of upper contact niece69 by a bolt 33 having a spacer portion 85 and cooperating with a locknut assembly 86, 87. A pin 79 engages an aperture 81 in the centralportion of. contact piece 69 and causes the hood 64to rotate withthecontact structure.

In operation, when the switch 16 is opened, the blade tip 46 will drawwith itthe contact structure so as to rotate it about shaft 70 in acounterclockwise direction in FIGURES 2 and 3. .When the contactstructure has rotated far enough that the end of the blade tip 46 comesfree of the jaws 66, 68, the rotary movement of the contact structurewill cease, while the opening motion of the blade 42 continues. The.electrical contact between the terminals 22 and 56 will be broken assoon as'the arcing rod 48 comes free'of the arcing horns 52 and 54in thecourse of the opening movement of the blade 42.

During the'closing'movemcnt, the blade-tip 46 slides between the jaws 66and 68 and rotates them back in a clockwise direction in FIGURES 2 and 3by means of the friction between the jaws and the blade tip. It will bereadily seen that a hinge-like motion occurs between the blade tip 46and the jaws 66, 68 at the beginning of the opening movement. Thishinge-like motion is very effective in breaking any ice which may haveaccumulated between the jaws and the blade tip. An improved wipingaction is also provided by this type of motion. 1

The jaws 66, 68 are flared so as to guide blade tip 46 into positionregardless of any misalignment. Hooks 78 and 84 (FIG. 4) are provided onthe upper jaw 68 for engagement with the edges 76 and 82 respectively,of the blade tip 46 in the event that, due to some misadjustment, theforce necessary to turn the contact structure should become greater thanthe frictional force between the blade tip and the jaws, so thatfriction alone would'be insufficient to turn the contact structure.

It will be seen that we have provided an extremely simple and effectiveself-aligning side-break switch for high-current and high-voltageoperation, It will be readily seen that numerous embodiments of ourinvention are possible, and we therefore do not desire to be limitedexcept by the scope of the following claims.

Having thus described the invention, what is claimed and desired to besecured by Letters Patent is:

1. An electrical switch having a plurality of insulators, one of saidinsulators being movable, a switch blade mounted on one of saidinsulators for movement into and out of contact with a contact structuremounted on another of said insulators, said switch blade beingjournalled for limited rotation about a pair of axes perpendicular toeach other and situated substantially in the plane of said movement intoand out of contact with said contact and separate pairs of relativelymovable contact surfaces on each of said pair of axes to form anelectrically conductive path around the journals for said switch blade.

2. An electrical switch having a plurality of insulators, a switch blademounted on one of said insulators for movement into and out of contactwith a contact structure mounted on another of said insulators, saidcontact structure comprising -a pair of contact members mounted forrotation and adapted to receive said switch blade between them, a pivotmeans for said contact members including springs mounted thereon forbiasing said contact members toward one another to grip said switchblade, and means spaced from the axis of rotation of said contactmembers for limiting the gap opening of said contact members.

3. An electrical switch having a plurality of insulators and a base, oneof said insulators being movable with respect to said base andsupporting a switch blade, said switch blade being mounted on saidinsulator for movement therewith, and terminal means mechanicallymounted on said insulator and electrically connected by said means tosaid switch blade, said terminal means being mounted for swinging andlimited rocking movement with respect to said insulator by rotatable androckable bearing means between said terminal means and said insulator.

4. An electrical switch having a pair of insulators, a contact on one ofsaid insulators adapted to receive a switch blade moving in apredetermined plane, a movable switch blade adapted to be received bysaid contact and a mounting for said switch blade on the other insulatoradapted to permit movement of said switch blade into and out ofengagement with said contact and, into the predetermined plane to bereceived by said contact, said mounting comprising, means for swingingsaid switch blade toward and away from said first contact, and meansincluding a pair of journals between said switch blade and said mountinglocated on axes perpendicular to each other adjacent to, and mountingsaid blade for, movement into said predetermined plane when received bysaid contact, means for limiting rotation of said blade on said journal,and means associated with at least one of said journals to predeterminethe frictional resistance to movement of said blade on one of saidjournals independent of the other.

5. The combination as defined in claim 4, in which the last said meansincludes electric contact surfaces on a member associated with one ofsaid journals.

6. An electrical switch having a pair of insulators, a contact on one ofsaid insulators adapted to receive a switch blade moving in apredetermined plane, a movable switch blade adapted to. be received bysaid contact, and a mounting for said switch blade on the otherinsulator adapted to permit movement of said blade into and out ofengagement with said contact and, into the predetermined plane to bereceived by said contact, said mounting comprising, means for swingingsaid switch blade toward and away from said first contact, meansincluding a pair of journals between said switch blade and said mountinglocated on axes perpendicular to each other adjacent to, and mountingsaid blade for, movement into said predetermined plane when received bysaid contact, means for limiting rotation of said blade on saidjournals, and means associated with said journals to predetermine thefrictional resistance to movement of said blade on said journals andincluding electric contact surfaces on separate members associated withsaid journals forming an electrically conductive path around saidjournals from said switch blade.

7. An electrical switch having a plurality of insulators, a switch bladeswingably mounted at one end on one of said insulators for movement ofits other end into and out of contact with a contact structure mountedon another of said insulators, said switch blade being journalled at itsswingably mounted end for limited rotation about one of a pair of axesperpendicular to each other and situated substantially in the plane ofsaid movement into and out of contact with said contact structure, saidswitch blade being journalled for swinging movement about the other ofsaid pair of axes, independently operating contact surfaces on each ofsaid pair of axes cooperating to form an electrically conductive patharound the journals for said switch blade.

8. An electrical switch having a pair of insulators, a switch bladeswingably mounted at one end on one of said insulators for movement ofits opposite end into and out of contact with a contact structuremounted on another of said insulators, said switch blade beingjournalled at its swingably mounted end for limited rotation about oneof a pair of axes perpendicular to each other and situated substantiallyin the plane of said swinging movement into and out of contact with saidcontact structure, said switch blade being journalled for swingingmovement about the other of said pair of axes, independently operatingcontact surfaces on each of said pair of axes cooperating to form anelectrically conductive path around the journals for said switch bladeand means for predetermining the frictional resistance to movement aboutone of said journals.

References Cited in the file of this patent UNITED STATES PATENTS2,193,122 Crabbs Mar. 12, 1940 2,303,914 Crabbs Dec. 1, 1942 2,709,739Gilliland et al May 31, 1955 2,780,684 Brown et al. Feb. 5, 19572,786,121 Bridges Mar. 19, 1957 2,791,651 Ortwig May 7, 1957

